Sulphuric acid derivatives

C. Reaction of Organometallic Compounds with Sulphurous Acid Derivatives... 

TABLE 8. Formation of sulphoxides, R2S=0, from the reaction of Grignard reagents with sulphurous acid derivatives, SOX2... 

The quantitative determination of the sulphuric acid derivatives may be carried out as described in the paragraphs above dealing with their qualitative analysis by decomposing the sample by warming with water or alkaline solutions and then determining the sulphuric and hydrochloric acids quantitatively. 

Sulphuric Acid Derivatives.—In the aliphatic series we considered the hydroxyl derivatives immediately following the halogen derivatives because in that series the hydroxyl compounds are directly and eeisily prepared from the halogen substitution products by the action of silver hydroxide, AgOH, or sodium hydroxide, NaOH. In the benzene series the halogen derivatives are followed by the sulphuric acid derivatives because, in the first place, the halogen derivatives are not converted into hydroxyl compounds by treatment with silver hydroxide, and in the second place, because the sulphuric acid derivatives of the benzene hydrocarbons are easily formed directly from the hydrocarbons by action of sulphuric acid, which was not the case in the aliphatic series and because they are exceedingly important as they are readily transformed into other classes of compounds, e.g, hydroxyl compounds, phenols. 

Sulphurous Acid Derivatives.— Just as we have the two acids of sulphur, sulphuric and sulphurous differing from each other by the amount of oxygen present, so we have benzene derivatives of sulphurous acid corresponding to the sulphuric acid derivatives, but containing one atom of oxygen less,... 

Sulphinic Acids.— These sulphurous acid derivatives are known as sulphinic acids in distinction from sulphonic acids. 

The enhanced sulphonating activity of sulphuric acid derivatives allows them to be used for the sulphonation of alkenes (this reaction is not possible with sulphuric acid). Thus, alkenic sulphonic acids are formed by the replacement of a vinyl hydrogen atom by the sulphonic acid group, as shown in equation ll98. 

Thermal analysis and Evolved Gas Analysis traces for sulphuric acid-derived PAA are shown in Figure 16. In marked contrast to phosphoric acid derived membranes, the heated sulphuric membranes display multi-stage weight loss behaviour and only two exothermic events are seen. Heated specimens generally retain their original planarity. 

The XRD data in Figure 17 show that no ciystalline phases were detected in sulphuric acid-derived PAA samples heated to 800 °C, comparable with the phosphoric PAA data in Figure 13. Step-wise heating to 900 °C and 1000 °C resulted in the formation of ccp y-alumina. At 1100 °C, the sample consisted mainly of 8-alumina, with a small amount of a-alumina (corundum). At 1200 °C only a-alumina was observed in the heated PAA... 

Fig. 17. XRD powder diffraction patterns of sulphuric acid-derived PAA heated to selected temperatures (CoKa radiation).

The pore architecture observed by SEM following heat treatment is shown in Fig. 19. On heating sulphuric acid-derived PAA membranes to 800 °C, the pore shape and size remain virtually unchanged. No overall shrinkage was observed at temperatures up to 1000 °C despite the weight loss and crystallisation processes. The basal face (Fig. 19, right) retains its open pore structure, in contrast to the pore closure observed in phosphoric acid membranes (Fig. 11, right). 

Fig. 19. SEM images of upper (left) and basal faces (right) of a sulphuric acid-derived PAA membrane heated to 800 °C.

The thermal decomposition data for HA PAA oxalic membranes is summarised in Figure 20, which shows evolved gas measurement data superimposed onto the thermal analysis trace. Comparable with sulphuric acid-derived membranes, but in contrast to phosphoric acid-derived membranes, 6 wt% is lost in a sharp exothermic reaction commencing at about 900 °C. Mass Spectrometry (MS) data shows that this is coincident with the loss of CO2 from the alumina lattice. A subsequent exothermic event centred at 1230 °C represents the... 

Sulphuric acid derived lignin exhibited the highest stability. In addition, it was shown that lignin from coniferous wood (spruce) was more stable than that of deciduous one (aspen, birch, oak). The authors stated that larger differences in DTA thermograms are found between different preparations of the same wood than between similar preparations of different woods. 

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